Support AUTO_INCREMENT in bin/storage adjust

Summary:
Ref T1191. When changing the column type of an AUTO_INCREMENT column, we currently may lose the autoincrement attribute.

Instead, support it. This is a bit messy because AUTO_INCREMENT columns interact with PRIMARY KEY columns (tables may only have one AUTO_INCREMENT column, and it must be a primary key). We need to migrate in more phases to avoid this issue.

Introduce new auto and auto64 types to represent autoincrement IDs.

Test Plan:

• Saw autoincrement show up correctly in web UI.
• Fixed an autoincrement issue on the XHProf storage table with bin/storage adjust safely.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T1191

Differential Revision: https://secure.phabricator.com/D10607